I think it’s also legal for Texas to make a law that’d allow them to arrest someone for travelling to Colorado with the intent to smoke weed
No, it’s not. The “commerce clause” in the Constitution gives Congress the power to regulate interstate commerce, not the states. States are separate legally. They can’t decide what other states do in their own territory, and they can’t pass laws restricting people traveling for that commerce.
If something is legal in one state and illegal in another, simply passing through a state to get to another literally can’t be restricted. This is the literal definition of the commerce clause, especially because healthcare in the US is a for-profit enterprise.
In fact, the healthcare facility could sue Texas in civil court for causing them damages by reducing their customers. It’s a direct harm to their business.